Parkflyers International Design and Build Log: Curtiss P-40 Warhawk

Discussion in 'Scratchbuilding!' started by bimoadiprakoso, Apr 19, 2017.

  1. PI P-40 with a new wing, thinner airfoil. Initially looked and flew very promising, seemed really stable wind or no wind and speed was good even against the wind but it didn't like to glide under 5 - 10km/h , it just dropped then. Just as it was about to touch down it just rolled over. Maybe going to move the cg back a bit.

     
  2. Well if all goes well, landings should be a breeze now at any speed. Programmed in what in FlySky tx says "Elev/Flaps" 2 hours later and 4 mixes it finally works. 7 out of 8 functions I could get to work properly but when I got number 8 working #7 would quit or wrong direction and so on went this merry-go-round. Just about cut in some flaps and install a couple more servos. ;)

    You can turn the function on or off but when it's on it is controlled by the elevator stick.

     
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  3. bogusbandit56

    bogusbandit56 Top Gun

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    Jeff I really don`t think that is correct.
    If you put flaps down for landing the elevators should go down.
    The flaps create more lift and pushes the nose up and with elevators going up it will push it into a loop and/or cause a stall when landing.
     
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  4. You know how long it took me to get this far!!!!! :D :D
     
  5. bogusbandit56

    bogusbandit56 Top Gun

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    Yes I do:D
    It took me a while to program flaperons for my gliders and my friend couldn`t figure it out at all.
    Anyhoo, would you prefer a heap of depron to take home in a bag?:D
    Well, just be careful:)
     
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  6. Play way up high. ;)
     
  7. bogusbandit56

    bogusbandit56 Top Gun

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    Jeff,
    If you remember we said the P.40 was notorious for tip stalling and that is why we had a fair chunk of undercamber on the wing tip.
    Both Paul and myself were amazed at how docile the PI P.40 was.
    Paul was saying that most war birds of this type had to be flown fairly fast and land at high speeds to prevent tips stalling.
    He loved the fact that this model could be flown at scale speeds. The thickness of the wing also plays a big part in the way it flies slowly.
     
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  8. PI P-40 with it's new wing and a new elev/flap setup, tried it up high a couple times and even on two approaches but chickened out on the last one and landed it without. Next time.

     
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  9. I did fly the P-40 today even though the video doesn't show it, stupid camera man. Loads of blue sky to see. :D A few fly byes it shows up, cruises rather well with the new wing but I have another idea for it. :)

     
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  10. bogusbandit56

    bogusbandit56 Top Gun

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    What was the outcome of the ele/flap mix. Couldn`t see much.
     
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  11. it works , I am sure I was below 5km/h with about 10% throttle , so same wing and it didn't fall on it's nose. Couple times you had to correct it quickly. I have to play with the settings a bit to take away a little of the elevator deflection.

    .
     
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  12. bogusbandit56

    bogusbandit56 Top Gun

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    How did you end up with the mix? The one you first had didn`t seem right to me it was down flaps and up elevator.
     
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  13. Still is. :) , I just need to tune out a little elevator from it without effecting normal elevator . One of the club members out there today when we were yacking about this setup, he did say (my memory fails again) whether it was high or low wing setup which I don't remember but certain planes would react just the opposite to the normal, so when flaps activated instead of pitching up these planes would pitch down. Beyond my data base. ;)
     
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  14. Start of a new experimental wing, staying with the thinner airfoil so it cuts through the air better but increasing the under camber portion and adding flaps. To help strengthen the wing tip also adding a 3mm cf rod into the top plate.
    Now having my FlySky Chinese elev/flap mix all 4 control surfaces will be active ailerons and when I flip the switch the active flap mix (controlled by the pitch stick) will be activated but will still have some aileron functions. Hopefully less tip stall and be able to float it in really slow.


    2018_0324_114421_001.JPG
     
  15. One new wing for the P-40, now to fit the hardware.



    2018_0324_171950_001.JPG 2018_0324_171958_002.JPG
     
  16. bogusbandit56

    bogusbandit56 Top Gun

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  17. Most of these airfoil type wings are the easy part, the fancy zillion tapered thin lines for the fuses and such are what take all the time.

    I have to print off a couple more of @Sterling101 servo trays, those work slick for recessing the servos with minimal amount of extra weight.
     
  18. One new wing complete with hardware and one old wing dissected from plane. :)

    2018_0325_090142_001.JPG 2018_0325_090150_002.JPG 2018_0325_091528_001.JPG 2018_0325_091534_002.JPG
     
  19. One new wing installed and working, just need to add the landing gear.

    2018_0325_102217_001.JPG
     
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  20. A short little video to somewhat explain this elev/flap mix.

     

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